Tilapia is the common name for a group of cichlid fish native to
North Africa and the Middle East [1,2]. Tilapia is the third most
important aquaculture fish species in the world. Selective breeding
for growth traits started in 1980s, leading to a substantial
improvement in growth performance [3]. Diseases are the major
bottleneck for sustainable and profitable aquaculture [4]. Streptococcus
agalactiae (S. agalactiae) is one of the causative agents
associated with warm-water streptococcosis, which causes
massive mortality in aquaculture [5]. The emergence of this disease
in tilapia farms usually occurs during high temperature season,
which causes tilapia to be more susceptible towards
streptococcosis [6]. Interactions between fish and pathogens, that
may be harmless under natural conditions, often result in serious
disease outbreak in aquaculture systems. Moreover, there are not
many effective approaches in conventional breeding for resistance
against this disease. Marker-assisted breeding for diseaseresistance
traits is believed to be an effective method for preventing
disease outbreak